I just had a system installed at my new house. We're drawing water from the lake. The rise from lake level to pump level is 12 feet. The line from the pump to the lake is a 1" line that is 235 ft long. The pump is a Berkeley 3/4 HP jet pump. I have a sediment filter, charcoal filter, and UV light installed, in that order, between the pump and the 44 Gal tank. The tank is pre-charged to 28 PSI, and the working water pressure is 30-53 PSI.

We had tried to set the pressure in the 40-60 range (with a pre-charge at 38), but the pump didn't seem to be able to get to 60. It topped out at 58 PSI and the pump continued to run trying to get it to 60. I tried turning the "shutoff" nut counter clockwise to lower the shutoff pressure to 55, but even with the nut loosened so that it wasn't applying pressure on the spring, I couldn't get the top-end
pressure to lower (ie: stop the pump).

Is 20 PSI the smallest diffential I should expect?

Is 58 PSI the highest pressure I should expect with this setup? Someone had mentioned getting a multi-stage pump (I'm assuming mine is a single stage) to have a higher top-end pressure.